The increasing possibilities for treating and correcting genetic disorders in human patients by approaches ranging from gene product replacement to gene transfer have created an increasing need for animal models in which to investigate pathogenetic mechanisms and approaches to therapy. The large reservoir of naturally-occurring counterparts of human genetic disease in animals, particularly domestic animals, has not been adequately utilized, in part because of the lack of accessible laboratories providing the special studies needed to identify and define genetic disorders in animals. The objective of this project is to provide a national referral center for the identification, characterization, evaluation, and dissemination of animal models of human genetic disease. The Center will provide consultation and laboratory studies of animals with signs suggestive of a useful new counterpart of human genetic disease. Laboratory studies include cytogenetics, screening for inborn errors of metabolism, identification of abnormal metabolites, and special and routine pathologic studies of biopsies and postmortem specimens. Family and breeding studies will be used to define modes of inheritance. Promising models will be made available to the general biomedical community in the form of cell cultures, DNA, frozen semen and breeding stock.